scholarly journals Non-invasive multi wavelengths sensorsystem for measuring carboxy-and methemoglobin

2017 ◽  
Vol 3 (2) ◽  
pp. 441-444
Author(s):  
Helge Gewiß ◽  
Ulrich Timm ◽  
Jens Kraitl ◽  
Beate Brock ◽  
Hartmut Ewald
Keyword(s):  
Blood Flow ◽  
Blood Gas Analysis ◽  
Minute Volume ◽  
Gas Analysis ◽  
Non Invasive ◽  
Hemoglobin Derivatives ◽  
Functional Derivatives ◽  
Invasive Method ◽  
Standard Pulse

AbstractStandard pulse oximetry only measures the functional derivatives oxyhemoglobin (O2Hb) and deoxyhemoglobin (HHb) to calculate the arterial oxygenation. However, the two dysfunctional hemoglobin derivatives carboxyhemoglobin (COHb) and methemoglobin (MetHb) are of much interest. The gold standard detecting abnormal concentration of COHb or MetHb is the blood gas analysis (BGA). In this paper a non-invasive method for measuring these derivatives and a setup for validation is presented.A standard pulse oximeter utilizes a sensor with two LEDs at the wavelengths 660 nm and 905 nm. For achieving information about the other hemoglobin derivatives, the new sensor is equipped with additional wavelengths between 500 nm and 1400 nm. An artificial blood-flow-model is used to simulate the blood flow through tissue. In this model a variation of the concentrations O2Hb, MetHb and COHb is feasible. The reflection of emitted light is measured for wavelengths between 500 nm and 600 nm, whereas transmission is measured for emitted light above 600 nm. An algorithm was designed to calculate the different hemoglobin derivatives independently. Therefore, the perfusion for each wavelength is computed and combined in a linear regression model.An in-vivo animal study with 18 pigs confirmed previous simulations. The pigs were ventilated with a respiratory minute volume of 4 l. To induce hypoxia (minimal SaO2 70 %), the inhaled air was mixed with nitrogen. Ventilating with 100 % oxygen reoxygenated the pigs. An increase of MetHb up to 35 % was induced by sodium nitrite. Afterwards methylene blue decreased the concentration. Carbon monoxide was mixed with the inhaled air to raise the COHb concentration up to 40 %. Different combinations of concentrations were performed. The references were achieved via BGA.It is shown that this setup is capable of measuring COHb, MetHb and O2Hb non-invasively. The setup is accurate even when manipulating hemoglobin derivatives in parallel.

Efficacy of Near-Infrared Spectrometry for Monitoring the Cerebral Effects of Severe Dilutional Anemia

2014 ◽  
Vol 17 (3) ◽  
pp. 154 ◽  
Author(s):  
Arıtürk Cem ◽  
Ustalar Serpil ◽  
Toraman Fevzi ◽  
Ökten Murat ◽  
Güllü Ümit ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Surgery ◽  
Blood Lactate ◽  
Near Infrared ◽  
Bypass Graft ◽  
Blood Gas Analysis ◽  
Gas Analysis ◽  
Infrared Spectrometry ◽  
Control Group ◽  
Near Infrared Spectrometry

<p><strong>Introduction:</strong> Clear guidelines for red cell transfusion during cardiac surgery have not yet been established. The current focus on blood conservation during cardiac surgery has increased the urgency to determine the minimum safe hematocrit for these patients. The aim of this study was to determine whether monitoring of cerebral regional oxygen saturation (rSO<sub>2</sub>) via near-infrared spectrometry (NIRS) is effective for assessing the cerebral effects of severe dilutional anemia during elective coronary arterial bypass graft surgery (CABG).</p><p><strong>Methods:</strong> The prospective observational study involved patients who underwent cerebral rSO<sub>2</sub> monitoring by NIRS during elective isolated first-time CABG: an anemic group (<em>N</em>=15) (minimum Hemoglobin (Hb) N=15) (Hb &gt;8 g/dL during CPB). Mean arterial pressure (MAP), pump blood flow, blood lactate level, pCO<sub>2</sub>, pO<sub>2</sub> at five time points and cross-clamp time, extracorporeal circulation time were recorded for each patient. Group results statistically were compared.</p><p><strong>Results:</strong> The anemic group had significantly lower mean preoperative Hb than the control group (10.3 mg/dL versus 14.2 mg/dL; <em>P</em> = .001). The lowest Hb levels were observed in the hypothermic period of CPB in the anemic group. None of the controls exhibited a &gt;20% decrease in cerebral rSO<sub>2</sub>. Eleven (73.3%) of the anemic patients required an increase in pump blood flow to raise their cerebral rSO<sub>2</sub>.</p><p><strong>Conclusions:</strong> In this study, the changes in cerebral rSO<sub>2</sub> in the patients with low Hb were within acceptable limits, and this was in concordance with the blood lactate levels and blood-gas analysis. It can be suggested that NIRS monitoring of cerebral rSO<sub>2</sub> can assist in decision making related to blood transfusion and dilutional anemia during CPB.</p>

scholarly journals Imaging of β-amyloid plaques by near infrared fluorescent tracers: a new frontier for chemical neuroscience

2015 ◽  
Vol 44 (7) ◽  
pp. 1807-1819 ◽  
Author(s):  
Matteo Staderini ◽  
María Antonia Martín ◽  
Maria Laura Bolognesi ◽  
J. Carlos Menéndez
Keyword(s):  
Near Infrared ◽  
Amyloid Plaques ◽  
Fluorescent Tracers ◽  
Non Invasive ◽  
Nir Imaging ◽  
New Frontier ◽  
Invasive Method ◽  
Β Amyloid

Near infrared (NIR) imaging is a promising and non-invasive method to visualize amyloid plaquesin vivo.

Abstract P225: Non-invasive Measurement of Renal Blood Flow (RBF) in Different Rat Models by Magnetic Resonance Imaging (MRI)

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Cesar A Romero ◽  
Robert Knight ◽  
Glauber Cabral ◽  
Oscar A Carretero
Keyword(s):  
Blood Flow ◽  
Sham Group ◽  
Motion Artifacts ◽  
Arterial Stenosis ◽  
7 Tesla ◽  
Hypertensive Rats ◽  
Rat Models ◽  
Non Invasive ◽  
Sd Rats ◽  
Invasive Method

Quantitative measure of RBF provides important information regarding renal physiology and pathology, in different animal’s models. Arterial Spin Labelling-MRI (ASL-MRI) is a non-invasive method to measure blood flow without exogenous contrast media, using arterial water protons labeled by radiofrequency as an endogenous tracer. However, the low signal/noise radio, and the motion artifacts are a challenge for the acquisition of RBF in small animals. Our objective is evaluated the feasibility and reproducibility of the RBF measure by ASL-MRI in different hypertensive rats models. ASL-MRI images were obtained in Sprague-Dawley (SD) rats (200-300g) under inhalation anesthesia using a 7 Tesla Varian MRI system with a spin echo imaging sequence. After 4 days the MRI studies was repeated to evaluate reproducibility, using paired sample T-test and the test-retest reliability (TR) equation. RBF was also measured in in Dahl SS rats on regular chow and spontaneous hypertensive rats (SHR). Additionally we measure the RBF in a set of animals under unilateral nephrectomy (UNx) and renal arterial stenosis (RS) before and after the surgery. Table 1 shows the mean cortical RBF in different rat strains and models. Re-test analysis showed no relevant differences, being the means of differences 9.4±35 ml/min/100g tissue (p=0.58) in SD rats. The TR was 92.4±6%. UNx increase the RBF in 69.1% in comparison with sham group. (p<0.01). After the RS the blood pressure increased and the RBF decrease 56% (p<0.01) in comparison with sham group. ASL-MRI performed with navigator correction and respiratory gating is a feasible and reproducible non-invasive method to measure RBF in several rat models.

scholarly journals 4D flow MRI for non-invasive measurement of blood flow in the brain: A systematic review

2020 ◽  
pp. 0271678X2095201
Author(s):  
Alasdair G Morgan ◽  
Michael J Thrippleton ◽  
Joanna M Wardlaw ◽  
Ian Marshall
Keyword(s):  
Blood Flow ◽  
Imaging Techniques ◽  
Acquisition Time ◽  
4D Flow ◽  
Non Invasive ◽  
Major Vessel ◽  
Dynamic Velocity ◽  
Blood Flow Dynamics ◽  
Cerebrovascular Imaging

The brain’s vasculature is essential for brain health and its dysfunction contributes to the onset and development of many dementias and neurological disorders. While numerous in vivo imaging techniques exist to investigate cerebral haemodynamics in humans, phase-contrast magnetic resonance imaging (MRI) has emerged as a reliable, non-invasive method of quantifying blood flow within intracranial vessels. In recent years, an advanced form of this method, known as 4D flow, has been developed and utilised in patient studies, where its ability to capture complex blood flow dynamics within any major vessel across the acquired volume has proved effective in collecting large amounts of information in a single scan. While extremely promising as a method of examining the vascular system’s role in brain-related diseases, the collection of 4D data can be time-consuming, meaning data quality has to be traded off against the acquisition time. Here, we review the available literature to examine 4D flow’s capabilities in assessing physiological and pathological features of the cerebrovascular system. Emerging techniques such as dynamic velocity-encoding and advanced undersampling methods, combined with increasingly high-field MRI scanners, are likely to bring 4D flow to the forefront of cerebrovascular imaging studies in the years to come.

Contrast-Free Blood Flow Velocity Profile Measurement With Ultrasound in Real-Time

2011 ◽  
Author(s):  
G. G. Koutsouridis ◽  
N. Bijnens ◽  
S. van Geldermalsen ◽  
P. J. Brands ◽  
F. N. van de Vosse ◽  
...  
Keyword(s):  
Blood Flow ◽  
Blood Velocity ◽  
Profile Measurement ◽  
Doppler Measurement ◽  
Non Invasive ◽  
Hemodynamic Variables ◽  
Vascular Impedance ◽  
Velocity Profile Measurement ◽  
Invasive Method ◽  
Flow Velocity Profile

In clinical practice, ultrasound is frequently used as a non-invasive method to estimate geometric properties of large arteries such as diameter and intima-media wall thickness and in a separate Doppler measurement hemodynamic variables such as blood velocity. For the purpose of deducing biomechanical parameters and hemodynamic variables that are related to the development of Cardiovascular Disease, such as compliance and vascular impedance, the assessment of only geometry and blood velocity is not sufficient. A simultaneous and non-invasive assessment of blood flow and blood pressure is required. This can only be obtained by an accurate and simultaneous measurement of the blood velocity distribution and wall motion, which is not feasible with the commonly used Doppler technique.

Design of an Ingestible Capsule With Wireless Communication and Powering Function for Obesity Treating

2013 ◽  
Author(s):  
Liang Yan ◽  
Tianyi Wang ◽  
Zongxia Jiao ◽  
Juanjuan Peng
Keyword(s):  
Morbid Obesity ◽  
Wireless Communication ◽  
In Vitro Experiments ◽  
Non Invasive ◽  
Removal Process ◽  
Wireless Control ◽  
Invasive Method ◽  
Energy Shortage

Intra-gastric balloons have been and effective and non-invasive method for morbid obesity treating since it is proposed. However, traditional balloons lead to complications such as nausea and sickness caused by insertion and removal endoscopes. Despite free of endoscope-guide insertion and removal process, wireless controlled balloons still have to face the problem of energy shortage. This paper proposes a novel wireless controlled and powered endoscope capsule of edible size. The performance of wireless control and powering are tested respectively. In addition, in-vivo and in-vitro experiments are conducted for further evaluation and shows feasibility for treating morbid obesity. This study may contribute to the development of endoscopic devices and surgery as well.

A Non-Invasive Method For Measuring Platelet Aggregation In Vivo

1981 ◽  
Author(s):  
J Morley ◽  
P M Hoyle ◽  
J Leyton ◽  
O J Davies
Keyword(s):  
Graphical Form ◽  
Functional Disturbance ◽  
Non Invasive ◽  
Hind Limbs ◽  
Minute Period ◽  
Invasive Method ◽  
Crystal Scintillation ◽  
Indium 111 ◽  
Aggregation And Disaggregation

In experimental animals, intravenous injection of ADP produces platelet accumulation in the lungs, together with thrombocytopenia. Since platelets can be isotopically labelled without gross functional disturbance, we have sought to develop a method for measurement of aggregation and disaggregation of labelled platelets in vivo.Guinea-pig platelets are labelled with Indium-111 and injected into narcotised animals (Sagital, 37 mg/kg). Two collimated crystal scintillation probes are used to monitor the thoracic region (heart and lung) (Cl) and the vascular compartment (hind limbs) (C2). An indwelling cannula (25 SWG) is inserted into a foot vein and kept patent by small volumes of heparin (100 u/ml). Intravenous ADP (10 mg/kg) causes transient accumulation of platelets within the lung, as well as thrombocytopenia, within a two minute period. During a response, counts are monitored from both probes and retained in a dedicated microcomputer, so as to permit rapid display of results in tabular and graphical form. Usually, ninety consecutive 4 sec. counts are recorded, results being expressed both as a paired difference (C1-C2) and as a ratio (C1/C2). Repeated challenge can be made with ADP and a dose-related response is obtained over the range 10-30 mg/kg. Treatment with sulphinpyrazone or prostacyclin inhibits aggregation.

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